Oil Sense

[gumby302ho]

 OK, I know some of you are shaking your head already but hear me out. The best thing for a four stroke in good running condition is good quality oil is the way I was raised. Just called local bike shop{40 years in the biz} very well known. I wanted to order some 20w50 motul full synthetic oil for the J and the gentleman said I dont need 20 50 and should run 10w40 blend, I explained the old J is air cooled and manual calls for it in warm temps, He could not believe it called for it and said save some money and go with 10w40 semi syn. Please set me straight. there is nothing wrong with running 20w50 in the J correct. Previous owner has 20w50 in bike right now. Proper warm up, I dont see an issue but only good protection. [ running stock cooler ] New Rpm shock and crash bars installed. I cant wait to try it.

[FJmonkey]

The new shock and crash engine guards won't care what oil you use. I am currently running a full synth 20-50, the only issue is clunky shifting till it properly warms up. So I would avoid it in the cooler regens/climates. Use good oil, change it regularly, ride it like you stole it....

[simi_ed]

If you're going to buy a case of Motul 20-50, I can probably save you some $$$ on a case of Amsoil in either 10W-40 or 20W-50.  And a superior oil filter to boot!    
Drop me a PM.

[fintip]

fjowners.wikidot.com/oil

FJ specific specs:
Engine/transmission oil:
Type API Grade SE or SF
Viscosity:
Up to 15°C (60°F): SAE 10W30
Above 5°C (40°F): SAE 20W40
Capacity:
With Filter change: 3.35 liters (3.5 US qt, 5.9 Imp pts)
Oil change only: 3.0 liters (3.2 US qt, 5.3 Imp pts)

also:

The smaller the ratio between the cold and hot "weights", the less additives needed, the better—thus, 10w40 is 1:4, and would be degrade faster than 20w50, which is 1:2.5. So, 20w50 > 10w40.

It's not clarified right there, but oil itself doesn't break down (unless it is burned); it is the additives that break down. To make an oil behave unnaturally (be thicker when it is hot than when it is cold) you have to use complex lab-designed molecules that are very long and have unique folding characteristics. Those are torn apart from mechanical stress of the engine over time, and as that happens, the oil becomes less and less able to thicken when heated, resulting in poorer lubrication.

[Pat Conlon]

If you live in a cold climate and ride durning the cold months, you want to use no heavier than the 10w-40.
On the cold start, your top end will thank you..

That is all....

[fintip]

(I should say, less able to thicken when heated, and less able to thin out when cooled--resulting in poorer lubrication when running, and harder starting.)

[gumby302ho]

The new shock and crash engine guards won't care what oil you use. I am currently running a full synth 20-50, the only issue is clunky shifting till it properly warms up. So I would avoid it in the cooler regens/climates. Use good oil, change it regularly, ride it like you stole it....
   Thanks for setting me straight on the crash bar grammar Monkey, I agree 100% on both counts, the use of the twenty weight oil as well.Some people I don't think are aware of how hot the summers can be up here for the folks further south, its a small window of riding but can be very scorching, hence 20w50 in my thumper and now in my J. Hope to learn how to show you good people some pics of my bike and miner cool mods like a new seat cover, im pumped! She has alot of rough edges but at a short glimpse she will make you focus, by that time she is already gone!